Fuel Pump Flow Rate ??????
Discussion
Anyone know what the Std chimera fuel pump on a 99 reg 450 later car is rated flow or roughtly what BHP its ok too. I have another thread going looks like mines dead but as its running mods is it best to go for an uprated pump or stick to factory fit? Idealy a straight swap to fit in same position.
I belive the standard Chimaera pump flows 100 litres per hour and should be good for anything upto 320hp, the Cerbera however was fitted with a higher flowing pump that could move 130 litres per hour which will serve a 400hp engine quite easily. I actually have a Cerbera pump on my car, mostly because I needed a replacement pump and a new old stock geniune Bosch unit came up for a very tempting price on Ebay at the time.
Keep in mind flow and pressure are very different things, rail pressure is managed by the fuel pressure regulator not the pump so I've had no issues running the higher flow Cerbera pump on my 250hp 4.0 litre Chimaera. The other factor that will influence flow is the size of your fuel lines, no matter how much your new pump flows there will come a point where your pipe work will start to determine peak flow. I believe Pupp (Gary) has just found the limits of the standard fuel lines on his Turbo conversion so it would be worth seeking his input.
One really important element that's very often overlooked is the wiring to the the pump, TVR could have made a much better job of it and it's not uncommon to get low meter readings at the pump with obviouse consiqueces. The fuel pump is actually switched by the ECU, while TVR did incorporate a relay it's in the passenger footwell so a good 7' from the pump itself which is less than ideal.
If you mount a fused relay closer to the pump, trigger it with existing low amp ECU output, then take a live feed from the battery through the relay direct to the pump you can be sure your pump is getting the full serving of volts and amps. Years ago I tested my pump by direct feeding it from the battery, before I'd even cheked the situation with my multimeter there was an immediate and extremely noticable difference in the sound the pump made.
With the original TVR wiring my pump would kind of moan and groan into life, with a decent high amp feed direct from the battery the pump positively buzzed away like an angry hornet. Try the direct feed test and see what you find, I bet you'll be surprised
More info with the genuine Bosche part numbers here:
http://www.pistonheads.com/gassing/topic.asp?t=142...
Keep in mind flow and pressure are very different things, rail pressure is managed by the fuel pressure regulator not the pump so I've had no issues running the higher flow Cerbera pump on my 250hp 4.0 litre Chimaera. The other factor that will influence flow is the size of your fuel lines, no matter how much your new pump flows there will come a point where your pipe work will start to determine peak flow. I believe Pupp (Gary) has just found the limits of the standard fuel lines on his Turbo conversion so it would be worth seeking his input.
One really important element that's very often overlooked is the wiring to the the pump, TVR could have made a much better job of it and it's not uncommon to get low meter readings at the pump with obviouse consiqueces. The fuel pump is actually switched by the ECU, while TVR did incorporate a relay it's in the passenger footwell so a good 7' from the pump itself which is less than ideal.
If you mount a fused relay closer to the pump, trigger it with existing low amp ECU output, then take a live feed from the battery through the relay direct to the pump you can be sure your pump is getting the full serving of volts and amps. Years ago I tested my pump by direct feeding it from the battery, before I'd even cheked the situation with my multimeter there was an immediate and extremely noticable difference in the sound the pump made.
With the original TVR wiring my pump would kind of moan and groan into life, with a decent high amp feed direct from the battery the pump positively buzzed away like an angry hornet. Try the direct feed test and see what you find, I bet you'll be surprised
More info with the genuine Bosche part numbers here:
http://www.pistonheads.com/gassing/topic.asp?t=142...
ChimpOnGas said:
I belive the standard Chimaera pump flows 100 litres per hour and should be good for anything upto 320hp, the Cerbera however was fitted with a higher flowing pump that could move 130 litres per hour which will serve a 400hp engine quite easily. I actually have a Cerbera pump on my car, mostly because I needed a replacement pump and a new old stock geniune Bosch unit came up for a very tempting price on Ebay at the time.
Keep in mind flow and pressure are very different things, rail pressure is managed by the fuel pressure regulator not the pump so I've had no issues running the higher flow Cerbera pump on my 250hp 4.0 litre Chimaera. The other factor that will influence flow is the size of your fuel lines, no matter how much your new pump flows there will come a point where your pipe work will start to determine peak flow. I believe Pupp (Gary) has just found the limits of the standard fuel lines on his Turbo conversion so it would be worth seeking his input.
One really important element that's very often overlooked is the wiring to the the pump, TVR could have made a much better job of it and it's not uncommon to get low meter readings at the pump with obviouse consiqueces. The fuel pump is actually switched by the ECU, while TVR did incorporate a relay it's in the passenger footwell so a good 7' from the pump itself which is less than ideal.
If you mount a fused relay closer to the pump, trigger it with existing low amp ECU output, then take a live feed from the battery through the relay direct to the pump you can be sure your pump is getting the full serving of volts and amps. Years ago I tested my pump by direct feeding it from the battery, before I'd even cheked the situation with my multimeter there was an immediate and extremely noticable difference in the sound the pump made.
With the original TVR wiring my pump would kind of moan and groan into life, with a decent high amp feed direct from the battery the pump positively buzzed away like an angry hornet. Try the direct feed test and see what you find, I bet you'll be surprised
More info with the genuine Bosche part numbers here:
http://www.pistonheads.com/gassing/topic.asp?t=142...
Dave this dont make sense why not just uprate the cable gauge to the relay and from relay to pump leave the relay where it is and do the same for the ground return Keep in mind flow and pressure are very different things, rail pressure is managed by the fuel pressure regulator not the pump so I've had no issues running the higher flow Cerbera pump on my 250hp 4.0 litre Chimaera. The other factor that will influence flow is the size of your fuel lines, no matter how much your new pump flows there will come a point where your pipe work will start to determine peak flow. I believe Pupp (Gary) has just found the limits of the standard fuel lines on his Turbo conversion so it would be worth seeking his input.
One really important element that's very often overlooked is the wiring to the the pump, TVR could have made a much better job of it and it's not uncommon to get low meter readings at the pump with obviouse consiqueces. The fuel pump is actually switched by the ECU, while TVR did incorporate a relay it's in the passenger footwell so a good 7' from the pump itself which is less than ideal.
If you mount a fused relay closer to the pump, trigger it with existing low amp ECU output, then take a live feed from the battery through the relay direct to the pump you can be sure your pump is getting the full serving of volts and amps. Years ago I tested my pump by direct feeding it from the battery, before I'd even cheked the situation with my multimeter there was an immediate and extremely noticable difference in the sound the pump made.
With the original TVR wiring my pump would kind of moan and groan into life, with a decent high amp feed direct from the battery the pump positively buzzed away like an angry hornet. Try the direct feed test and see what you find, I bet you'll be surprised
More info with the genuine Bosche part numbers here:
http://www.pistonheads.com/gassing/topic.asp?t=142...
you wont get any notable loss between the relay contacts by being in the standard location (front) 
I think the wire gauge is fine for the job at hand its far more likely to have poor grounding that causes the low voltage at the pump terminals often reported IMO or is it because its friday and I have misinterpret your post? 
Edited by Sardonicus on Friday 17th June 14:56
You don't need to go adding additional relays. when the issue is the cable size to the pump plus a possible earth issue simply replace cable with slightly larger guage cable for the supply and ground back to the relay and job done , this should get rid of any volt drop and give you a good ground
The Bosch 044 is a fine pump that will give you the capacity should you desire to go for tuning in the future
Otherwise go standard
The Bosch 044 is a fine pump that will give you the capacity should you desire to go for tuning in the future
Otherwise go standard
Edited by Hoofa on Friday 17th June 17:10
Edited by Hoofa on Friday 17th June 17:10
Sardonicus said:
ave this dont make sense why not just uprate the cable gauge to the relay and from relay to pump leave the relay where it is and do the same for the ground return you wont get any notable loss between the relay contacts by being in the standard location (front) I think the wire gauge is fine for the job at hand its far more likely to have poor grounding that causes the low voltage at the pump terminals often reported IMO or is it because its friday and I have misinterpret your post?
Thats what I meant you wont get any notable loss between the relay contacts by being in the standard location (front) I think the wire gauge is fine for the job at hand its far more likely to have poor grounding that causes the low voltage at the pump terminals often reported IMO or is it because its friday and I have misinterpret your post? 
... cable gauge upgrade and earth return, actually I went Canems which comes with a new improved fuel pump loom anyway 
Before that I did have one fuel pump related breakdown I traced to connector corrostion, as we know the pump sits in a location very vulnerable to moisture.
Post Canems instalation my pump collected a piece of swarf from my new aluminium tank and killed it dead, thats when I added the Cerbera pump but mostly because it was the only new genuine Bosch I could find at the time at a reasonable price, I paid special attention to proctecing the terminals with a smear on petrolium jelly covering them with rubber terminal boots.
Worked a treat
Edited by ChimpOnGas on Friday 17th June 19:19
ChimpOnGas said:
That what I meant, cable gauge upgrade and earth return, actually I went Canems which comes with a new improved fuel pump loom anyway
Before that I did have one fuel pump related breakdown what I traced to connector corrostion, as we know the pump sits in a location very vulnerable to moisture.
Post Canems instalation my pump collected a piece of swarf from my new aluminium tank and killed it dead, thats when I added the Cerbera pump but mostly because it was the only new genuine Bosch I could find at the time at a reasonable price, I paid special attention to proctecing the terminals with a smear on petrolium jelly covering them with rubber terminal boots.
Worked a treat
Ah get it Before that I did have one fuel pump related breakdown what I traced to connector corrostion, as we know the pump sits in a location very vulnerable to moisture.
Post Canems instalation my pump collected a piece of swarf from my new aluminium tank and killed it dead, thats when I added the Cerbera pump but mostly because it was the only new genuine Bosch I could find at the time at a reasonable price, I paid special attention to proctecing the terminals with a smear on petrolium jelly covering them with rubber terminal boots.
Worked a treat
yeh EFI pumps dont like ingesting solids 
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